Trees Holslag is involved in amongst others in the purchase, sale and encumbrance of commercial real estate, the division into apartment rights of large buildings, the creation of long lease in industrial areas, vesting of mortgages as securitisation of loans and the sale of newly built apartments.

She has also been involved in the creation of legal structures with respect to park management in industrial areas, and legal structures for PPS cooperations such as the incorporation of partnerships and companies and the crafting of shareholders agreements.